Facilities for the reprocessing of irradiated nuclear fuel materials are equipped with so-called hot cells for holding the components needed for conducting the industrial processes associated therewith. In these radiation-shielded cells, the process components are arranged in scaffold-like structures or racks as they are sometimes referred to.
The maintenance work within the hot cell affected by radioactive radiation should be conducted preferably without the necessity of operating personnel entering the hot cell. Solutions have been therefore sought to conduct the maintenance work by means of remotely-controlled equipment which can be movable within the hot cell. For this purpose, it is desirable that the racks holding the components used in the industrial processes be arranged in mutually adjacent rows longitudinally along the walls of the hot cell. In this way, a center passageway is formed along which the remotely-controlled equipment for the maintenance work can be moved and fully-loaded racks can be exchanged.
It is intended that a remotely-controlled manipulator carrier system be arranged in this passageway which will make it possible to reach the process components from this position by acting in the horizontal direction. With this manipulator carrier system, service and maintenance apparatus as well as tools are positioned. The manipulator carrier system opens up the possibility of using servo-manipulators and power manipulators as well as robots and/or programmed devices. With manipulators and lifting devices presently available, manual-like operations can be performed with small components in dependence upon the extendible arm of the carrier system.
The manipulator carrier system essentially includes a vertical guide column which is connected to the movable bridge beam of an overhead bridge assembly arranged to travel above the process components in the direction of the longitudinal axis of the large-area cell. The guide column can be mounted so as to be rotatable about its longitudinal axis and can be supported on the floor of the passageway. The rotatable guide column includes an extendible arm mounted on a support movable in the vertical direction. The extendible arm can be provided with the tools or a manipulator or other remotely-controlled device.
The extendible arm is often configured as a telescopically extendible arm in order to reach different work locations at respectively different depths in the racks. However, the deeper that the work location is in the rack, the higher will be the bending moment applied to the arm. To enable the extendible arm to take up an adequate load, it is desirable to keep the length to which the arm has to be extended to a minimum.